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ABSTRACT Flexoelectricity, defined as polarization induced by strain gradients, is especially pronounced in two‐dimensional (2D) materials due to their mechanical flexibility and sensitivity to deformation. In nanostructures with nanometer‐scale curvature, bending can perturb out‐of‐plane π orbitals and generate quantum‐mechanical polarization and electrostatic modulation beyond classical lattice distortion alone. Here, we combine scanning probe measurements and first‐principles calculations to provide experimental and theoretical evidence for large intrinsic quantum orbital flexoelectricity in graphene nanowrinkles (GNWrs) with estimated polarization densities of P_th∼ 4 C m⁻²and P_exp∼ 1 C m⁻², exceeding those of mesoscale systems by 5 to 7 orders of magnitude. These GNWrs exhibit high apex curvature, undergo atomic‐level buckling, and produce localized strain fields, as supported by atomic force microscopy analysis and Raman spectroscopy. Kelvin probe force microscopy reveals curvature‐dependent work‐function shifts, while conductive atomic force microscopy detects reproducible GNWr‐associated currents with a threshold voltage (Φ_th∼ 1 V) comparable to the band offset predicted by ab initio calculations (∼ 1.2 V). These results support an interpretation in which curvature‐induced flexoelectric dipoles reshape the local electronic potential. GNWrs therefore provide a structurally simple carbon‐based platform for probing quantum‐mechanical flexoelectricity. 

Large gas bubbles can reach the surface of pools of mud and lava where they burst, often through the formation and expansion of circular holes. Bursting bubbles release volatiles and generate spatter, and hence play a key role in volcanic degassing and volcanic edifice construction. Here, we study the ascent and rupture of bubbles using a combination of field observations at Pâclele Mici (Romania), laboratory experiments with mud from the Imperial Valley (California, USA), numerical simulations and theoretical models. Numerical simulations predict that bubbles ascend through the mud as elliptical caps that develop a dimple at the apex as they impinge on the free surface. We documented the rupture of bubbles in nature and under laboratory conditions using high-speed video. The bursting of mud bubbles starts with the nucleation of multiple holes, which form at a near-constant rate and in quick succession. The quasi-circular holes rapidly grow and coalesce, and the sheet evolves towards a filamentous structure that finally falls back into the mud pool, sometimes breaking up into droplets. The rate of expansion of holes in the sheet can be explained by a generalization of the Taylor–Culick theory, which is shown to hold independent of the fluid rheology. 

We used temperature-dependent spark plasma sintering to induce phase transformations of metastable 3D c-BN to mixed-phase 3D/2D c-BN/h-BN and ultimately to the stable 2D h-BN phase at high temperature, useful for extreme-temperature technology. 

Abstract Ceramic composites exhibiting the combination of light‐weight, semiconducting behavior, low thermal conductivity, and solid‐state lubrication are crucial for advanced applications in electronics, thermal insulation, and wear‐resistant components, enabling efficient performance under demanding conditions. However, obtaining these functionalities simultaneously in a single material is nontrivial because these properties often require opposing structural and compositional features. Here, the synthesis of spark plasma sintered SiOC‐BN ceramic composite by combining amorphous silicon oxycarbide (SiOC) with crystalline hexagonal boron nitride (h‐BN) is reported. Comprehensive structural and microscopic characterizations confirm the existence of uniformly distributed h‐BN and cubicβ‐SiC phases throughout the bulk material. The composite exhibits ap‐type semiconducting behavior with nearly isotropic electrical resistivity and low cross‐plane thermal conductivity at room temperature. Mechanical and tribological testing further reveal the excellent strength and solid‐state lubrication under high mechanical loads, with a low coefficient of friction. Comparative structure‐property correlations with individual SiOC and h‐BN ceramics highlights the synergistic effects of the combined phases, contributing to the composite's properties. These findings show the potential of SiOC‐BN ceramic composite as a promising material for future technologies.